In the present applicant's above cited related applications and patent the invention disclosed and claimed is utilized to visually determine the presence of oily contaminants in aqueous streams. Although the invention is applicable to any type of aqueous stream or effluent, the said invention is particularly illustrated therein for issues associated with marine bilgewater discharge. In the instance of bilgewater the primary sources of the contaminants are vessel propulsion systems and auxiliary systems that use fuels, lubricants, hydraulic fluid, antifreeze, solvents and cleaning chemicals. Certain waste streams such as steam condensate, boiler blowdown, drinking fountain water, and sink drainage located in various machinery spaces can also drain to the bilge.
Currently, commercial and military surface ships primarily employ two different methods in dealing with bilgewater treatment and removal. Many of these vessels use oil-water separator systems to reduce the oil content of bilgewater prior to overboard discharge. Most of these large vessels also have onboard systems for collecting and transferring bilgewater to a holding tank for later removal and disposal on shore.
In the present inventor's U.S. Pat. No. 6,475,393 (see also related U.S. Pat. No. 6,180,010), it is disclosed that the compositions described in the inventor's U.S. Pat. Nos. 5,437,793; 5,698,139; and 5,837,146, and 5,961,823 (all of which disclosures are hereby incorporated by reference) have extremely strong affinities for the contaminants in oily bilgewater; and that when oily bilgewater streams containing these noxious contaminants are passed through filtration media incorporating these compositions, the contaminants are immobilized at the media. As a result, concentration levels of the contaminants in the filtrate may be reduced to very low values, in some instances below detectable limits in a single pass. This feature not only enables ready removal of oils, greases, and similar materials from the bilgewater, but also allows removal of pernicious, slightly soluble organic compounds such as benzene, toluene, xylene, halogenated hydrocarbons, ethoxylated glycols, and the like. These noxious contaminants are among the more difficult compounds to remove from water, and indeed most are carcinogenic. The solubility of the foregoing substances renders most prior art physical separation methods generally ineffective and causes formation of stable and pseudostable oily emulsions (micelle size of 400 micrometers or less), which also do not respond well to gravity separation due to neutral buoyancy.
In accordance with these prior patents, the bilgewater can be passed through one or more filters incorporating the principles of the earlier inventions, prior to the bilgewater being actually discharged from the vessel. The filter or filters may simply be placed directly in the bilgewater discharge line, for example, downstream of the bilgewater pump effecting the discharge flow. In a test of a typical such installation, the test results included removal of all sheen and visible discharge.
More specifically, the method of the prior invention may be described as one of passing the bilgewater through a fluid-pervious filtration media which has been infused with an absorption composition comprising a homogeneous thermal reaction product of an oil component selected from the group consisting of glycerides, fatty acids, alkenes, and alkynes, and a methacrylate or acrylate polymer component; the contaminant being thereby immobilized at the media. For convenience these absorption compositions may hereinafter be referred to as “MACs”, a term derived from “Mycelx absorbent compositions”, where “Mycelx” is not used as a technical descriptor but merely as a reference to the assignee of the aforementioned patents pertaining to the said compositions and methodology. It will be appreciated that the MACs used in the present invention are not limited to the specific absorption compositions disclosed in the aforementioned U.S. patents, but also may include for example, additional compositions falling within the aforementioned description of the compositions, such as improvements upon the previously patented compositions which yet remain within the technical description stated immediately above in this paragraph.
Filter configurations incorporating the MACs may be based on various water permeable substrates, such as shredded, spun or otherwise configured polypropylene or shredded or spun cellulose, which substrates are infused or otherwise treated with the absorbent compositions, which are then cured. These substrates may then be packed or otherwise disposed in a cartridge or canister filter, or the substrates can be formed into cured and infused bag filters which can be emplaced in canisters through which the contaminated bilgewater is flowed. Similarly, the said absorbent compositions can be incorporated into or upon other filtering substrates and media if desired, including for example, paper, compressed pulp materials, particulate porous foamed plastics, mineral particulates such as perlite and vermiculite, and particulate, fibrous or porous ceramic or porous (for example, sintered) metal substrates and media.
In the course of utilizing bilgewater filtration systems, including those based upon the foregoing principles, it is often difficult to determine the quality of effluent from oily water separators without relying on sensor readings or other means. Moreover, it is often not possible even to determine visually if the separator unit itself is on or off. The capability to perform a rapid visual inspection of a filtration system would be useful for quickly determining when the capacity of the filtration system has been exceeded. However, the inability to perform simple visual inspections has led to accidental oily bilge water discharge and can even lead to criminal prosecution of the individuals responsible. In the case of oily water treatment devices, it is not possible to effectively use transparent sight gauges or glass indicators on the housings or in the connecting piping, due to the tendency of the surfaces over which the discharge flows to become opaque from oily fouling. Difficulties such as this arise not only in bilgewater, but also in numerous aqueous process streams where it is at least equally important to be rapidly made aware of the presence of oily contaminants. The presence of oily contaminants can arise for many reasons other than filtration failure or overload, as for example from accidental or other unintended leakage of oily contaminants into the process stream.
Many issues arising from oily contaminants in aqueous streams also can arise in connection with gaseous streams. An example of how these issues can arise in gaseous systems is seen in so-called “clean rooms” that are used in modern high technology manufacturing and processing operations, in health and medical facilities, and in various laboratories, and the like. The air in such clean rooms acquires small but deleterious quantities of oily contaminants, commonly in the form of suspended or dispersed particulates, which can arise from the operating equipment and other devices present in the clean room and from the mechanical and electrical means by which air is circulated in such rooms. To attempt to remove such contaminants in the air of a clean room, the air typically is constantly formed into a gaseous stream and subjected to filtration, often with highly effective HEPA and/or other filters.
Among the filters that are effective in gaseous and air filtration are those disclosed in the present inventor's U.S. Pat. No. 6,805,727, in which the filter used is one in which a gaseous media containing suspended oily particles is passed through a fluid pervious media which has been treated with an absorption composition cured in situ at the media and comprising a homogeneous thermal reaction product of an oil component selected from the group consisting of glycerides, fatty acids, alkenes, and alkynes, and a methacrylate or acrylate polymer component. The contaminant, on contact with such a filtration media, is thereby immobilized on the filter. Regardless of the effectiveness of such filtration, either as a result of continuing use, wear and tear in other parts of the filtration system, or other reasons, the undesired contaminants can leak into the output gas from the filtration system. However, it is of utmost importance to be assured that the undesired oily contaminants are not present in significant amounts in the working environment of the clean room, and it is therefore desirable to be promptly apprised of the quality of the filtration system output gas with respect to presence therein of such oily contaminants.
Therefore, what is needed generally is an apparatus and/or method for visually determining the presence of oily contaminants, including those very small size oily droplet which are present as particulates suspended or dispersed in a gaseous stream. More specifically, what is needed is an indicator device and method that allows for visually examining a gaseous stream to determine the presence therein of such contaminants. The capability to perform a rapid visual inspection of a filtration system would be useful for quickly determining when the capacity of any gaseous filtration system has been exceeded or when there has been any type of failure of the system.